At what stage did it occur to Daniel Levy that he would have to appoint a new manager this summer to replace Tim Sherwood?

The cynics -- of which I'm unapologetically a member -- would say that Levy knew that he would have to from the very moment that he handed Sherwood an 18-month contract. So given that Tottenham have had so long to ruminate on who their next manager would be, why are they still yet to appoint one? After all, Manchester United have already confirmed Louis van Gaal as their new manager, having only decided to sack David Moyes in April.

The Dutchman and what he represents could well be the answer to the question. Van Gaal flirted with the idea of taking over Spurs, only to run off towards United when they fluttered their eyelashes at him.

It's been clear that LVG was Manchester rather than London bound for some time now but that doesn't mean that it's been easy for Levy to move on. Van Gaal was the one type of manager that Levy has yet to appoint -- a proven winner that has enjoyed success at every club he's been in charge of.

With van Gaal off the menu, promising young managers such us Mauricio Pochettino and Frank de Boer have emerged as the favourites to take the reigns at White Hart Lane. Both have much to offer but undoubtedly have question marks regarding their respective abilities.

Pochettino has enjoyed success at Espanyol and Southampton but more will be expected in the more pressurised atmosphere at Tottenham. He has done wonders with the players that he's inherited at St Mary's, yet has a mixed record in the transfer market. Is he someone that Levy can trust to build a team?

De Boer has experience of managing a big club in the shape of Ajax, where he's won four consecutive titles. Despite this success, some will argue that a well-run Ajax will always dominate in Holland, especially in an era where their competitors possess little financial muscle. Indeed, the lack of financial resources in Dutch football has meant that De Boer's astuteness at the top end of the transfer market remains untested.

Put simply, either man would represent a gamble, even if their known qualities make it a calculated risk. You can have your opinion as to whether either would prove successful at Spurs but unless you're in possession of a DeLorean time machine, you can't state that opinion with complete assurance.

With an older manager like van Gaal, it is easier to look back at his past achievements and have a sense of what you're getting for your money. This is such a vital appointment for Levy that he won't want to get it wrong. Van Gaal was the type of appointment that would have reduced that possibility. Of course, Van Gaal is not the only experienced manager out there. Rafa Benitez has been mentioned as a contender and the Napoli manager has succeeded in just about every job he's undertaken, apart from his brief spell at Inter Milan.

What marks Benitez and van Gaal apart is the style of football that their teams tend to play. Benitez employs a pragmatic style that might not prove popular with a Tottenham crowd that grew weary of Andre Villas-Boas' tactics. Levy's choice of manager not only needs to be successful but also placate an increasingly rebellious support. In this sense, Pochettino or De Boer might be a safer bet than Benitez.

It's hard to find a manager that ticks every box but there is one man out there who fits that description and just might become available. Carlo Ancelotti has won trophies with clubs in four countries and has Premier League experience. He is used to dealing with huge pressure and tricky owners. His sides also play good football and Ancelotti manages to remain popular with his players, despite many of them being among the most high profile in the world.

Ancelotti would be as close to a perfect manager as Levy could appoint. He would have to leave Real Madrid first but if they failed to win the Champions League on Saturday, that could become a distinct possibility at a club that expect even more of their managers than Levy himself. At this moment it remains a long shot but with the other candidates unlikely to receive more attractive offers than the Spurs job, Levy can afford to bide his time for a few more days.

The chance of perfection comes around rarely. Having missed out on van Gaal, you can be sure that Tottenham will wait and see if they have a chance of appointing a manager that would please everyone.